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Microsecond Protein Dynamics from Combined Bloch‐McConnell and Near‐Rotary‐Resonance R 1 p Relaxation‐Dispersion MAS NMR
Author(s) -
Marion Dominique,
Gauto Diego F.,
Ayala Isabel,
GiandoreggioBarranco Karine,
Schanda Paul
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201800935
Subject(s) - microsecond , chemistry , relaxation (psychology) , dispersion (optics) , protein dynamics , molecular dynamics , magic angle spinning , resonance (particle physics) , isotropy , molecular physics , nuclear magnetic resonance , amplitude , millisecond , chemical physics , computational chemistry , physics , atomic physics , nuclear magnetic resonance spectroscopy , optics , quantum mechanics , psychology , social psychology
Studying protein dynamics on microsecond‐to‐millisecond ( μ s‐ms) time scales can provide important insight into protein function. In magic‐angle‐spinning (MAS) NMR, μ s dynamics can be visualized by R 1 ρrotating‐frame relaxation dispersion experiments in different regimes of radio‐frequency field strengths: at low RF field strength, isotropic‐chemical‐shift fluctuation leads to “Bloch‐McConnell‐type” relaxation dispersion, while when the RF field approaches rotary resonance conditions bond angle fluctuations manifest as increased R 1 ρrate constants (“Near‐Rotary‐Resonance Relaxation Dispersion”, NERRD). Here we explore the joint analysis of both regimes to gain comprehensive insight into motion in terms of geometric amplitudes, chemical‐shift changes, populations and exchange kinetics. We use a numerical simulation procedure to illustrate these effects and the potential of extracting exchange parameters, and apply the methodology to the study of a previously described conformational exchange process in microcrystalline ubiquitin.